<!DOCTYPE html>
<html>
<head lang="en">
    <meta charset="UTF-8">
    <title></title>
    <style>
        * { margin: 0 ; padding: 0; }
        #father {
            width: 200px;
            height: 200px;
            background-color: #f77c3d;
            margin: 30px ;
        }
        #son { 
            width: 100px; 
            height: 100px;
            background-color: #CC00FF;
        }
    </style>
</head>
<body>

<div id="father">
    <div id="son"></div>
</div>

<script>
window.onload = function(){
    var son = document.getElementById('son');
    var father = document.getElementById('father');
    son.onmouseout = function(event){
        /*maoPao(event);
        function maoPao(event){
            var event = event || window.event;
            if ( event.stopPropagation ){
                return event.stopPropagation();//主流浏览器
            }else{
                return event.cancelBubble = true;//ie678
            }
        }*/
        var event = event || window.event;
        if ( event.stopPropagation ){
            return event.stopPropagation();//主流浏览器
        }else{
            return event.cancelBubble = true;//ie678
        }
    };
    father.onmouseout =function(){
        alert( '鼠标离开父盒子啦' );
    };
}


</script>

</body>
</html>